This invention is concerned with filter systems, and more particularly with filter systems having a filter unit that is cleaned without interrupting the normal operation of the filter unit.
In most cases cleaning of a filter, such as an air filter at the intake manifold of an automobile engine, requires that the normal operation of the filter be interrupted. There are circumstances, however, when interruption of the normal operation of the filter is intolerable--for example, when continuous operation of an engine in dust-laden air is necessary, or when frequent filter cleaning is required due to operation of the engine in heavily dust-laden air. Moreover, filters tend to become loaded with intercepted (filtered) material, creating an increase in the pressure difference across the filter, and hence a loss of engine power. The more highly efficient the filter medium, the greater is the percentage of airborne contaminant material collected, and the higher the engine power loss in a given period of time. Reducing the filter medium efficiency is not an appropriate answer to this problem, however, because the resulting increase in airborne contaminant ingested by the engine can cause engine power loss and damage and shorten engine performance life. To avoid the foregoing problems, cleaning of a filter in situ, without interrupting the normal operation of the filter, is highly desirable.